spiral 
a spiral line, a spiral), < L. spiraea, coil, spire: see 
spire-.] I. a. 1. Of or pertaining to a spire 
or coil ; like a spire ; 
pointed or shaped like 
a spire. 2. Winding 
around a fixed point 
or center, and contin- 
ually receding from it, 
like a watchspring; 
specifically, in cuiu-li., 
making a number of 
turns about the col- 
nmella or axis of the 
shell; whorled. The 
whorls may be in one plane, 
producing the flat or dis- 
coid shell, or oftener wound 
5839 
spire 
2. A helix or curve which winds round a cylin- spiration (spi-ra'shon), . [< LL. tpiratto(n-), 
der like a screw. 3. A spiral spring. 4. Ii 
wool, one of the eurls or convolutions in wool- 
fiber, the number of which in a unit of length is 
made the basis of an estimate of its quality for 
manufacturing. 5. In :ofil. and anat., a spiral 
formation, as of a univalve, of the cochlea, etc. 
Airy'S spirals, the peculiar colored interference flgiires 
seen when two sections of quartz, one of a right-handed 
the other of a left-handed crystal, hoth cut transverse 
to the vertical axis, are placed one over the other, and 
viewed in converging polarized light. Curschmann's 
spirals, invatlutl., bodies formed of spirally wound mu- 
cous threads with often a fine shining central thread. 
They seem to be casts of small bronchi, and are eipecto- 
a breathing, < L. xpirarc, pp. xiiirtitiin. breathe, 
blow, exhale: see spire 3 .] 1. A breathing. 
God did by a kind of spiration produce them. 
Barrow, Sermons, II. xxxiv. 
2. In tlieol., the net by which the procession of 
the Holy Ghost is held to take place ; also, the 
relation or notion so constituted. 
spire 1 (spir), . [Also spear (formerly also 
speer), now commonly associated with spnn ' : 
< ME. spire, spyre, spir, < AS. spir, a stalk, = 
MLG. spir, LG. spier, a point, needle, sprout, 
= G. spier, a needle, pointer, spiere, a spar, = 
Flat Spiral of an Ammonite (An 
monites bifrons). 
rated in asthma and certain forma of bronchitis. Dou- Icel. spira, a spar, stilt, a kind of beaker, = Sw. 
CO1U alien, Ul WJl/CIIcl l*ullv 
into a spire, resulting in the ordinary turreted form. Com- 
pare cuts under Planorbis and Limneea, and see spires, 2. 
3. Winding and at the same time rising or ad- 
vancing like a screw-thread: more accurately 
lii-liral or lielicoidal. 
Where upward, in the mellow blush of day, 
The noisy bittern wheeled his spiral way. 
Longfellow, Sunrise on the Hills. 
Spiral axis. See oxisi . Spiral balance, a form of bal- 
ance in which the weight of the body 
under examination is measured by the 
stretching (torsion) of an elastic wire in 
the form of a long spiral. A common 
use of the staple form of spiral balance 
(see cut) is in determining the specific 
gravity of small fragments of minerals, 
which for this purpose are weighed first 
in the upper pan and then in that be- 
low, which is immersed in water. Spi- 
ral canal of the cochlea, of the mo- 
diolus. See canali, and cut under earl. 
Spiral duct, in bot. t same &s spiral ves- 
sel Spiral fracture.a fracture of bone 
due to torsion, so that the broken ends 
have a more or less screw-like appear- 
ance. Spiral gearing. See gearing. 
Spiral layer, the middle one of the 
three layers or coats of the tracheal wall 
in insects. See txnidium and trachea. 
Spiral ligament of the cochlea, 
the spiral ridge at the outer insertion of 
the basilar membrane : it is prismatic, 
or triangular in section. Spiral line, 
the line connecting the radii or radiating 
lines of a geometrical spider's web, and 
forming a continuous spiral from the 
circumference nearly to the center. It 
is formed after the radii have been put 
in place. Spiral nebula, phyllotax- 
is, plexus. See the nouns. Spiral 
point. See spires, 3. Spiral ptero- 
pods, the Limacinidie. Spiral pump, a form of the 
Archimedean screw water-elevator. See Archimedean 
screw, under Archimedean. Spiral screw. See screw*. 
Spiral space, the area bounded at its two ends by 
successive parts of the same radius vector, and within 
and without by successive parts of the same spiral. 
Spiral spring. See spring. Spiral valve, in ichth., 
a continuous fold or ridge of mucous membrane which 
winds spirally about the interior of the intestine of 
some fishes, as ganoids. Spiral vessel, in bot., a ves- 
sel which is usually long, with fusiform extremities, and 
has the walls thickened in a spiral manner with one 
or more simple or branched bands or 
fibers. In most cases the direction of the 
spiral is from right to left, but it fre- 
quently happens that the earlier formed 
spirals run in one direction, while those 
formed later run in an opposite direction. 
See tissue, vessel. Spiral Wheels, in 
math. See wheel. 
H. K. 1. In geom., a plane curve 
which runs continuously round 
and round a 
fixed point, 
called the een- 
Spiral Balance for 
determining spe- 
cific gravities. 
We, equiangular, logarithmic, loxodromic spiral. 
See the adjectives.- Logistic spiral. Same as logaritk- 
mic spiral (which see, under logarithmic). Norwich spi- 
ral, that second involute of the circle whose apse is mid- 
way between the cusp of the first involute and the center 
of the circle : so called because first shown by Sylvester at 
the meeting of the British Association at Norwich in 1888. 
Parabolic spiral. See parabolic^, and cut above, 
spiral (spi'ral), r. t. ; pret. and pp. spiraled, 
spiralled, ppr. spiraling, spiralling. [\ spiral, 
n.] To make spiral; cause to move spirally. 
The teeth of the cutter should be made to run slightly 
spiralled. Joshua Rose, Practical Machinist, p. 346. 
spirality (spi-ral'i-ti), n. [< spiral + -ity.] 
Spiral character or quality. Science, III. 583. 
spirally (spi'ral-i), adv. In the form or man- 
ner of a spiral. 
spiral-tail (spi'ral-tal), n. The royal or king 
bird of paradise, Cincinnurus regitts: so called 
from the spiral coil at the end of the middle 
tail-feathers. See cut under Cincinnurus. 
spiramentt, . [< L. spiramentum, a breathing- 
hole, air-hole, < spirare, breathe: see spire 9 .] 
A spiracle. Rev. T. Adams, Works, I. 78. 
spirant (spi'rant), n. [< L. ypiran(t-)s, ppr. of 
spirare, breathe, blow, exhale : see spire 3 .] A 
consonant uttered with perceptible blowing, or 
expulsion of breath ; an alphabetic sound in the 
utterance of which the organs are brought near 
together but not wholly closed ; a rustling, or 
fricative, or continuable consonant. The term 
is by some restricted to sounds of the grade of and /, the 
(ft of thin and that of thine, and the German eft; others 
make it include also the sibilants ; others, the semivowels 
/' and y. 
Spiranthes (spi-ran'thez), n. [NL. (Eichard, 
1818), so called in allusion to the spiral arrange- 
ment of the flowers ; < Gr. mrelpa, a coil, spire, 
npira, a spar, scepter, pistil, = Dan. spire, a 
spar, germ, shoot, spir, a spar, spire (in arch. ) ; 
perhaps connected with spikel and spine, or 
with spear 1 .] 1. A sprout or shoot of a plant. 
An ook comth of a litel spire. Chaucer, Troilus, ii. 1335. 
2. A stalk of grass or some similar plant; a 
spear. 
Shal neuere spir springen vp. 
Piers Plowman (C), xiii. 180. 
Pointed Spires of Flax, when green, 
Will Ink supply, and Letters mark unseen. 
Congrcve, tr. of Ovid's Art of Love. 
3. The continuation of the trunk in a more 
or less excurrent tree above the point where 
branching begins. 
No tops to be received, except the spire and such other 
top or limb as may be grown on the main piece [British 
oak for navy contracts). Laslett, Timber, p. 72. 
4. A name of various tall grasses, as the mar- 
ram, Ammophila arundinacea; the reed canary- 
grass, Phalaris arundinacea; and the common 
reed, Phragmites communis. Britten and Holland, 
Eng. Plant Names. [Proy. Eng.] 5. In mining, 
the tube carrying the train to the charge in the 
blast-hole : so called from the spires of grass or 
rushes used for the purpose. Also called reed or 
rush. 6. A body that shoots up to a point; a 
tapering body; a conical or pyramidal body; 
specifically, in arch. , the tapering 
part of a steeple rising above 
the tower; a steeple; the great 
pinnacle, often of wood covered 
with lead, frequently crowning 
the crossing of the nave in large 
churches. 
E the flowers; < Gr. mrelpa, a coil, spire, churches. The earliest spires, in the 
flower.] A genus of orchids, of the architectural sense, were merely pyram- 
- - - - -- ~ - -- ij a i or conical roofs, specimens of 
which exist in some of the oldest Roman- 
esque buildings. These roofs, becoming 
gradually elongated and more and more 
acute, resulted at length in the graceful 
tapering spire. Among the many exist- 
ing medieval examples, that of Salisbury 
Cathedral is one of the finest; that of 
tribe Neottiex, type of the subtribeS/nranWiea-. 
It is characterized by commonly spirally ranked and some- 
what ringent flowers with the upper sepal and the two pet- 
als erect or connivent and galeate, and the lateral sepals 
set obliquely on the ovary or long-decurrent, and by a 
column not prolonged into a free appendage, but usually 
decurrent on the ovary. There are about 80 species, wide- 
Parabolic Spiral. Archimedean Spiral. 
Spiral Vessels 
or Ducts of E<- ter, with constantly increasing ra- 
r""m.'" '' dius vector, so that the latter is 
never normal to the curve ; also, a 
part of such a curve in the course of which the 
radius from the center describes 360. Besides 
the spirals mentioned below, the involute of the circle and 
the cyclodes are very important. The principal spirals 
which have received attention are the spiral of Archi- 
medes(usually understood 
to have been discovered 
by Conon the Samian), the 
radius of which increases 
uniformly with the angle ; 
the hyperbolic spiral, 
whose radius vector is in- 
versely proportional to 
the angle ; the lituus, the 
square of whose radius vector is inversely proportional to 
the angle ; and the logarithmic spiral, whose angle is pro- 
portional to the logarithm of the radius vector. 
Hyperbolic Spiral. (Less of the 
inner part of one branch is shown 
than of the other.) 
. 
ly dispersed through temperate and tropical regions of 
both hemispheres. They are terrestrial herbs from a short 
rootstock or a cluster of fleshy fibers or thickened tubers. 
Many species produce small white or greenish fragrant 
flowers, in several spirals forming a dense spike ; in some 
the spike is reduced to a single spiral or becomes straight 
and unilateral. The flowers are commonly small, but reach 
a large size in some tropical American species. The leaves 
are usually narrow, often grass-like. Six species are na- 
tives of the northeastern United States, all late-flower- 
ing and some of them then leafless. They are known as 
lady's-tresses, &'. cernua also locally as wild tuberose, and 
S. graciKs as corkscrew-plant. 
spiranthic (spi-ran'thik), a. [<s]>irantli-y + -ic.] 
Of the nature of or affected with spiranthy. 
Spiranthy (spi-ran'thi), n. [< Gr. aire'ipa, a coil, 
spire (see spire 2 ), + avftoc, a flower.] In bot., the 
abnormal dislocation of the organs of a flower 
in a spiral direction. Thus, Masters describes a curi- 
ous flower of Cypripedium insigne, in which a displace- 
ment occurred by a spiral torsion proceeding from right 
to left, which involved the complete or partial suppression 
of the organs of the flower. Also spelled speiranthy. 
spiraster (spl-ras't&r), n. [NL., < Gr. amlpa, 
a coil, spire, + aarr/p, a star.] In sponges, an 
irregular polyact spicule in the form of a stout 
spiral with thick spines ; a spinispirula. When 
these spines or rays are terminal, the spicule is 
called an amphiaster. Sollas. 
Spirastrosa (spir-as-tro'sa), n. pi. [NL.: 
see spirastrose.] In Sollas's classification of 
sponges, a group of choristidan tetractinellidan 
sponges, generally provided wifli spirasters. 
spirastrose (spl-ras'tros), a. [< spiraster + 
-ose (see *.._' ' 
spicules in the form of spirasters ; of or pertain- 
ing to the Spirastrosa : distinguished from ster- 
rastrose. 
spirated (spi'ra-ted), a. [< spire? + -atel + 
-ed?.] Formed into or like a spiral; twisted like 
a corkscrew. See cut under sasin. [Bare.] 
Themalesof this species [Anlilopebezoartica] have long, 
straight, spirated horns nearly parallel to each other, and 
directed backward. Darwin, Descent of Man, II. 236. 
I 
Spire of Senlis 
Senlis Cathedral, France, though not of 
great size, is one of the earliest of fully 
developed spires, and is admired for the 
purity and elegance of its design. The 
spires of medieval architecture are gen- 
erally square, octagonal, or circular in 
plan ; they are sometimes solid, more 
frequently hollow, and are variously or- 
namented with bands encircling them, 
with panels more or less enriched, and 
with piercings and spire-lights, which 
are of infinite variety. Their angles 
are sometimes crocketed, and they are 
often terminated by a flnial. In later 
examples the general pyramidal outline 
is obtained by diminishing the diameter 
of the structure in successive stages, and 
this has been imitated in modern spires, Cathedral, France; 
in which the forms and details of classic 'y '3* century, 
architecture have been applied to an 
architectural creation essentially medieval. The term 
spire is sometimes restricted to signify such tapering 
structures, crowning towers or turrets, as have parapets 
at their base, while when the spire rises from the exterior 
of the wall of the tower, without the intervention of a 
parapet, it is called a broach. See also cuts under broach, 
10, rood-steeple, and transept. 
The glorious temple rear'd 
Her pile, far off appearing like a mount 
Of alabaster, topt with golden spires. 
Milton, P. R., iv. 548. 
7. The top or uppermost point of a thing ; the 
summit. 
To silence that 
Which, to the spire and top of praises vouch'd, 
Would seem but modest. 
Shak., Cor., i. 9. 24. 
! (spi-ras'tros), a. [<. spiraster f 
MS).] Having microscleres or flesh- spire 1 (spir), P.; pret. and pp. spired, ppr. spir- 
ing. [< ME. spiren, spyren (= Dan. spire = Sw. 
spira, germinate); < spire 1 , n.~\ I. intrans. 1. 
To sprout, as grain in malting. 2. To shoot; 
shoot up sharply. 
Yon cypress spiring high, 
With pine and cedar spreading wide 
Their darksome boughs on either side. 
Wordsworth. White Doe of Rylstone, iv. 
II. trans. If. To shoot or send forth. 
